CHAPTER IV: WILDLIFE HABITATS FOR MISSISSIPPI’S SGCN,
THREATS AND CONSERVATION ACTIONS^233P etit Bois, Horn, Ship (East and West) and Cat Islands in Mississippi and Dauphin Island in Alabama
form a chain of barrier islands in the North central Gulf Region. In Mississippi, the islands are situated
about 12 miles from the mainland where they form the south shore of Mississippi Sound. The islands
serve as the boundary between the marine and estuarine systems of Mississippi's coastal wetlands.
Waters north of the islands are considered estuarine. The Sound, which ranges in salinity from nearly
fresh to 30 parts per thousand (ppt), serves as a large mixing zone for fresh and marine waters.
The barrier islands were formed by westward drift (often called "Longshore Drift") of sands from the
Floridian shores, movement that continues today, although channel dredging for shipping lanes causes
some disruption of sand movement and probably reduces the amount of deposition along the islands.
The extent of this westward drift is exemplified by the movement of Petit Bois Island, which connected
to Dauphin Island in the 1700's and is now located about four miles west of Dauphin Island. Round and
Deer Islands are mainland remnants isolated by rising sea level. Some of their habitats are similar to the
barrier islands and may be included in island habitat descriptions below.
This type includes seven subtypes: 13.1 Barrier Island Uplands, 13.2 Man-Made Beaches, 13.3
Barrier Island Wetlands, 13.4 Mainland Beaches, 13.5 Barrier Island Beaches, 13.6 Shell Middens
and Estuarine Shrublands and 13.7 Maritime Woodlands.
GENERAL CONDITION
Many of the barrier island habitats, parts of which are considered wilderness, remain in good condition,
but hurricanes have caused overwash and additional destabilization of the fragile dune systems. The
barrier islands are gradually diminishing in size by wave erosion and reduced sand accretion. Exotic
weeds, which have gained footholds on the mainland in pine flatwoods and savannas, live oak
woodlands and shell middens, as well as on the islands, continue to reduce the condition of these
landscapes.
Like other coastal states, the use of coastal areas as industrial, urban and residential centers has disturbed
much of the natural landscape surrounding coastal wetlands in Mississippi. Over half of the U.S.
population lives within 50 miles of the coast and this population is growing at a much faster rate than
inland regions. This rapid urbanization of our coasts has destroyed a significant amount of coastal
wetlands and fringe habitats, degraded coastal water quality and severely stressed other coastal